I figured the catchlights had to do with flash or other type of lighting... but our wedding photographer took engagement pictures a few months ago and only uses natural night, no flash at all, and there were catchlights every time! I was so confused? Does this mean she did it in photoshop.

As for natural light... I know to shoot about an hour before sunset but how do I know what angles to use? How to I get that sharp, perfectly lighted image every time? (I'm not asking that much, right!?)

1 - Interesting. Could have been a natural catchlight - even if the photog was wearing a white shirt.... Also could have been added in PP.

2 - Haha - wouldn't it be nice to have that answer. Many different scenarios - just read as much as you can. You're right though, the lower in the sky the sun is, the softer the light.

As for angles, this really depends, many different schools of thought and depends on the conditions. Generally - shoot people when it's cloudy if possible. If that's not possible, get them in the shade, but with sun nearby. If that's not possible, shoot them with the sun over their shoulders and fill with flash.

People will disagree, as there are different opinions, but this is lighting 101 with many people photogs.

Catchlights are simply the eyes reflecting some source of light. It can be a window, soft boxes, bounced or more direct sources ... Direct flashes and even those bounced can create tiny little (and, personally, not so attractive) pinlights in the eyes. The light must be defined, though. You can often tell what type of light was used in creating a catchlight...
http://www.geekinspired.com/wp-content/uploads/2008/07/catchlights_02.jpg - Umbrella